Reinforcing bar



April 5, 1938.

F. A. HENDERlC H 2,113,322

REINFORCING BAR Filed Dec. 10, 1936 L fr'ed k/q. He22de77/b/L $4341 Gum/wags Patented Apr. 5, 1938 UNITED STATES PATENT OFFICE 3 Claims.

forcing bars commonly used in concrete constructions. As is well understood, metal reinforce bars, embedded in concrete structures resist tensional strains imposed on the concrete mass and aid in preventing fracture of said mass under pulling forces greater than the tensile strength of the concrete itself. Of course, the resistance afforded by the reinforce bar is dependent upon several factors, one of which is the adhesion or bond between the body of concrete and the bar. As a smooth bar would not bond with the concrete to any great extent, the tensile strength of such a bar would be utilized to a very slight extent and it has, therefore, previously been proposed to deform the bars and produce protuberances on the surface thereof to increase the bond between the bar and concrete. However, if such protuberances or projections are formed Without undue waste of material, considerable portions of the surface of the bar are, nevertheless plain and do not aid to any extent in effecting a bond between the bar and concrete. The principal object of the present invention, therefore, is to provide a bar which will possess a maximum bonding effect, so to speak, when embedded in a concrete body. In the preferred embodiment of the invention, the entire surface of the bar aids in effecting a bond with the concrete. At the same time, the bar is of uniform cross-sectional area throughout its length.

With these and other objects in view, the invention consists in certain details of construction and combinations and arrangements of parts, all as will hereinafter be more fully described, and the novel features thereof particularly pointed out in the appended claims.

In the accompanying drawing- Figs. 1 and 2 are side views, taken at right angles to one another, illustrating in plan a bar made according to the preferred embodiment of the present invention.

Figs. 3 and 4 are transverse views on the lines 33 and 4-4, respectively, of Fig. 1.

Fig. 5 is a plan view illustrating a modified form of the invention.

The present bar may be made of any desired cross-sectional configuration but, as illustrated, it is preferably rectangular. In order to secure maximum bonding efiects, the entire combined area of the four sides of the bar are so formed that one-half of said combined area will resist tensional strains in one direction and the other half will resist strains in the opposite direction. This result is obtained by forming successive por- This invention relates to improvements in reintions of the bar of wedge-like shape. Each two successive wedge-like portions merge into each other, but are reversely disposed longitudinally of the bar. For instance, one portion of the bar, indicated at I0, is formed with one diameter, indicated at A, gradually decreasing in the direction of the arrow in Fig. 1, while the diameter, indicated at B, at right angles to diameter A, gradually increases. In the next adjacent increment or portion ll of the bar, the diameter A gradually increases while diameter B gradually decreases. Thus, oppositely inclined surfaces merging into each other are formed on each face of the bar throughout the length'of the latter with the adjoining surfaces of the several faces merging at the same points longitudinally of the bar. As before stated, this arrangement results in one-half of the total surface of the bar resisting relative longitudinal displacement of itself and. the concrete in one direction while the other half of said total surfaces resists like strains in the opposite direction. Accordingly, a maximum bonding of the bar, and the concrete in which it is embedded, is obtained. Furthermore, for the amount of metal in the bar, each individual inclined surface on the bar possesses a maximum area or, in other words, the bar is provided with so-called bonding surfaces of maximum area for cooperation with the larger and, therefore, stronger particles of aggregate in the concrete in .preventing relative movement of the concrete and bar under tensional strains.

By making the bar of the same general crosssection, for instance, rectangular, throughout its length, it is possible to form the same with a substantially uniform cross-sectional area over its entire length. For instance, if the present bar is made one square inch in section, at the points where each two inclined portions II], I I, join (indicated by line F) the bar will be nine-tenths of an inch by ten-ninths of an inch, while at a point midway each individual portion (indicated by line H), which represents the point of greatest increase in cross-sectional area between each two points F, thecross-sectional area will be increased .0111 or slightly over one (1) per cent. This is important because, by holding this increasein cross-sectional area to a minimum or, in other words, having the bar of substantially uniform cross-sectional area, not only is the weight of the bar minimized, but just so much metal is saved. Furthermore, the present bar has a constant perimeter-4.022 plus inches for the one-inch barand, as previously observed, the benefit of this surface is obtained in the bonding action.

What I claim is:

1. A reinforcing bar for concrete, the crosssectional shape of said bar constantly changing, one diameter thereof being alternately gradually reduced and increased with the diameter at right angles thereto being alternately gradually increased and decreased to form oppositely inclined adjoining wedge-like surfaces longitudinally of the bar, adjoining surfaces merging directly into each other throughout the length of the bar whereby surfaces parallel to the longitudinal axis of the bar are eliminated.

2. A reinforcing bar for concrete, the cross sectional shape of said bar varying throughout the length thereof, one diameter of said bar being alternately reduced and increased with the diameter at right angles tothe first-mentioned diameter being alternately increased and reduced to form oppositely inclined wedge-like surfaces longitudinally of the bar, the surfaces of opposite inclination merging into one another, whereby surfaces parallel to the longitudinal axis of the bar are eliminated, and the variations in the cross-sectional shape of said bar being of an order to maintain a substantially uniform crosssectional area throughout the length of the bar.

3. A reinforcing bar for concrete, the cross-sectional shape of said bar constantly changing, one diameter thereof being alternately gradually reduced and increased with the diameter at right angles thereto being alternately gradually increased and decreased to form oppositely inclined adjoining wedge-like surfaces longitudinally of the bar, adjoining surfaces on each side of the bar merging directly into one another throughout the length of the bar whereby surfaces parallel tothe longitudinal axis of the bar are elimihated, and with the points at which adjoining surfaces of like inclination of the several sides merge coinciding to form a bar of rectangular cross-section throughout its length. 7

FRED A. HENDERICH. 

